Many security and observation systems in the prior art use conventional video technology, employing standard video cameras to record a scene and video cassette recorders (VCR's) to store the video signals generated. Examples of such systems include Peterson U.S. Pat. No. 4,789,904 and Cotton et al. U.S. Pat. No. 4,630,110. The Peterson patent also discloses a microphone for pick-up and recording of accompanying audio information. Such systems have a number of disadvantages, including having numerous moving parts which wear and must be replaced, as well as the requirement of periodically rewinding the videotape. Additionally, communication of the continuous video signals to a remote location for observation must be over high-grade video cables instead of cheaper and more convenient telephone lines utilizing modems.
Other video-based systems employ continuous loop videotapes, which never need to be rewound. Examples of these systems include Dennis et al. U.S. Pat. No. 4,054,752 and Rosenbaum U.S. Pat. No. 3,885,090. There are also systems geared toward specific applications. See Milatz U.S. Pat. No. 4,942,464, Roy et al. U.S. Pat No. 4,876,597, and Lapidot U.S. Pat. No. 4,758,888, where the camera is stationary and therefore has a limited field of vision, and where there is no provision for pick up and recording of accompanying audio information.
There remains a need for a system which is mobile and transportable, can adapt to the ambient lighting conditions, can transmit a still frame color video with an accompanying audio in real time, and is capable of being interrogated from a remote location.